1. Field of the Invention
The invention relates to seats which include vibration compensating suspension mechanisms. More particularly, the invention relates to a seat including an improved knee action suspension mechanism.
2. Reference to Prior Art
Seats of vehicles such as trucks are subject to substantial vibration as the vehicles travel over rough road surfaces. A majority of seats now made for operators of such vehicles include a vibration compensating suspension mechanism beneath the seat. Such suspension mechanism are in addition to the vehicle suspension systems which interpose the wheels of the vehicle and the vehicle bodies.
One type of suspension mechanism is the knee action suspension mechanism of the general type disclosed in U.S. Pat. No. 3,711,149. An improved type of knee action suspension mechanism is the floating knee pivot suspension mechanism disclosed in U.S. Pat. No. 4,949,930. For the knee action suspension mechanism disclosed in U.S. Pat. No. 4,949,930, it is required to operate a lever mounted on the chassis housing and an air valve connected to the air spring, thereby occupying both hands, in order to adjust the height of the seat cushion relative to the base. Also, when the height of the seat is changed, the air spring must be readjusted in order to control the ride, i.e., the upward bias of the pivot arm assembly, provided by the air spring.